The ferromagnetic to paramagnetic transition in nickel studied by angular-resolved photoemission from single crystals

Abstract

Photoemission measurements ($\hslash \omega =16.8\mathrm{}$ eV and $\hslash \omega =21.2\mathrm{}$ eV) on the three high-symmetry faces (111), (100), and (110) of nickel have been performed. Specifically the temperature of the sample was varied to measure both the ferromagnetic and the paramagnetic state. The results obtained cannot be interpreted within the Stoner-Wohlfarth band model of ferromagnetism, if a value 0.3-0.5 eV of the exchange splitting is valid. However, a model, based on an intra-atomic exchange interaction, acting on the itinerant $d$ electrons, is capable of explaining the data.